JP2008163803A - Centrifugal compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifugal compressor performing a high pressure ratio and providing efficient supercharging over the whole area from a small flow rate area to a large flow rate area. <P>SOLUTION: In a supercharging compressor 1, an impeller 3 is enclosed in a housing 2. A diffuser 4 is formed on the peripheral side of the impeller 3, and further, a scroll chamber 5 is formed around the diffuser 4. The scroll chamber 5 is formed with a winding start portion 10 having a small channel diameter and a winding ending portion 11 having a large channel diameter. The winding start portion 10 and winding ending portion 11 join, communicate, and form a tongue portion 6. The tongue portion 6 is provided with a movable wall 8 closing the tongue portion 6 by spring force of a spring 9. The movable wall 8 closes the tongue portion 6 in the small flow rate area. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a centrifugal compressor used for a turbocharger or the like assembled in an engine mounted on a vehicle.

Conventionally, a turbocharger that improves the output of an engine by mixing pressurized air with increased density with fuel and burning it has been put into practical use, and such a turbocharger includes a centrifugal compressor.

Such a centrifugal compressor has, as a basic structure, an impeller (impeller) driven by a turbine in a housing, a diffuser formed around the impeller, and a circumferential shape on the outer peripheral side of the diffuser. It has a scroll room.
By the way, a centrifugal compressor used for an engine mounted on a vehicle, that is, an intake compressor in a turbocharger, is used from a small flow rate to a large flow rate. It has been difficult to simultaneously satisfy the requirements for maintaining efficiency. In order to realize high-efficiency supercharging over the entire area corresponding to such flow rate characteristics, for example, a proposal as in Patent Document 1 has been proposed. Patent Document 1 includes a ring-shaped leaf spring member that forms part of the vaneless diffuser wall surface and the scroll chamber wall surface, and uses the inner diameter end of the leaf spring member as a fixed end and an outer diameter. The end portion is configured as a free end portion, and the flow path diameter in the vaneless diffuser portion is variable by deformation of the fixed end portion due to movement of the free end portion side, while the free end portion is configured to have a flow path diameter in the scroll chamber A movable wall member that is movable so as to be variable is connected, the movable wall member and the leaf spring-like member are interlocked, and an actuator for operating the movable wall member is provided.

Japanese Utility Model Publication No. 63-83499

  The configuration disclosed in Patent Document 1 includes a pressure ratio (outlet pressure / inlet pressure) in a large flow rate region by increasing the flow path diameter in the vane-less diffuser section and the flow path diameter of both the scroll chambers, the efficiency, and the both flow path diameters. The purpose is to improve the efficiency of the small flow area by reducing the flow rate.

  However, the configuration disclosed in Patent Document 1 is a device that covers the entire scroll chamber formed in a circumferential shape, and the configuration is complicated.

  Then, this invention makes it a subject to provide the centrifugal compressor which can obtain a high pressure ratio and can implement | achieve efficient supercharging over the whole region from a small flow volume range to a large flow volume range.

  In order to achieve the above object, the centrifugal compressor of the present invention is characterized in that a movable wall is provided for changing the communication state between the winding start portion and the winding end portion of the scroll chamber (claim 1). In addition, a movable wall for changing a communication state between the winding start portion and the winding end portion is provided at a tongue portion where the winding start portion and the winding end portion of the scroll chamber merge (claim 2). . The scroll chamber is formed in a circumferential shape around the diffuser. The flow path diameter at the winding start portion is small (the flow path area is small), and the flow passage diameter at the winding end portion is large (the flow path area is large). That is, the flow path diameter of the scroll chamber gradually increases from the winding start portion to the winding end portion. The winding start portion and the winding end portion are joined and communicated with each other at the winding end portion that makes a round from the winding start portion, and a so-called tongue portion is formed at the portion. When the winding start portion and the winding end portion communicate with each other in the tongue portion, air is recirculated in the scroll chamber. It is considered that the recirculation of air in the scroll chamber may cause a reduction in supercharging efficiency. Therefore, the present invention is provided with a movable wall that changes the communication state between the winding start portion and the winding end portion of the scroll chamber, thereby improving the supercharging efficiency in each flow rate region.

  In such a centrifugal compressor, the movable wall protrudes toward the scroll chamber side in a small flow rate region, and the communication between the winding start portion and the winding end portion can be blocked (Claim 3). . It is considered that the reduction in supercharging efficiency due to the air recirculation in the scroll chamber is particularly remarkable in a small flow rate region where the recirculation flow rate is high. Therefore, by blocking communication between the winding start portion and the winding end portion in the small flow rate region, efficient supercharging in the small flow rate region can be realized.

  In such a centrifugal compressor, the movable wall may be configured to include an elastic body that biases toward the scroll chamber side. The movable wall appears and disappears in the scroll chamber according to the pressure in the scroll chamber.

  Furthermore, such a centrifugal compressor can be configured to include an actuator that moves the movable wall into and out of the scroll chamber and a control unit for the actuator. The movable wall protrudes and appears in the scroll chamber according to the state of the centrifugal compressor, such as the rotational speed of the centrifugal compressor. With such a configuration, the supercharging can be improved by controlling the communication state between the winding start portion and the winding end portion of the scroll chamber.

  According to the present invention, since the movable wall that changes the communication state between the winding start portion and the winding end portion of the scroll chamber of the centrifugal compressor is provided, the centrifugal compressor extends from the small flow rate region to the large flow rate region. Efficient supercharging can be realized.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram showing the periphery of the tongue 6 of the supercharged compressor 1 of this embodiment as a cross section. 2A and 2B are views of the supercharged compressor 1 viewed from the direction of the rotation axis, and are explanatory views showing the arrangement and shape of the scroll chamber 5. FIG. The supercharged compressor 1 forms a turbocharger mounted on a vehicle and corresponds to the centrifugal compressor of the present invention. The supercharged compressor 1 has an impeller 3 built in a housing 2. A diffuser 4 is formed on the outer peripheral side of the impeller 3. Further, a scroll chamber 5 is formed around the diffuser 4. The scroll chamber 5 is formed in a circumferential shape, and as shown in FIGS. 2A and 2B, a winding start portion 10 having a small channel diameter and a winding end portion 11 having a large channel diameter are provided. Is formed. Such a winding start part 10 and the winding end part 11 merge and communicate with each other, and a so-called tongue part 6 is formed at the location.

  The tongue portion 6 of the housing 2 is formed with a storage portion 7 in which a movable wall 8 that closes the tongue portion 6 is stored. A spring 9 disposed on the back side of the movable portion 8 is accommodated in the storage portion 7 together with the movable wall 8. This spring 9 corresponds to an elastic body in the present invention, and biases the movable wall 8 so as to push it out to the scroll chamber 5 side. The spring force (repulsive force) of the spring 9 is set according to the specifications of the supercharged compressor 1. That is, when the pressure in the scroll chamber 5 is low in the small flow rate region, the movable wall 8 is pushed out and the communication between the winding start portion 10 and the winding end portion 11 is interrupted, and the pressure in the scroll chamber 5 is increased in the large flow rate region. When the height is high, the movable wall 8 is set to have a spring force that allows the winding start portion 10 and the winding end portion 11 to communicate with each other as being pushed into the storage portion 7.

  Next, the operation of the supercharged compressor 1 configured as described above will be described. First, when the pressure in the scroll chamber 5 is low during operation in a low flow rate region, the winding is performed as shown in FIG. Communication between the start portion 10 and the winding end portion 11 is blocked. For this reason, the air flowing through the scroll chamber 5 is discharged to the outside as indicated by the arrow 12 without recirculating through the scroll chamber 5. Thereby, the loss by recirculation can be avoided and supercharging can be performed efficiently in a small flow rate range.

  On the other hand, when the pressure in the scroll chamber 5 is high during operation in a large flow rate region, the movable wall 8 receives the high pressure in the scroll chamber 5 and is pressed against the storage unit 7 side. When this pressing force exceeds the spring force of the spring 9, the movable wall 8 starts to move, and the winding start portion 10 and the winding end portion 11 are brought into communication as shown in FIG. For this reason, a part of the air flowing in the scroll chamber 5 is branched from the flow indicated by the arrow 12 and recirculated in the scroll chamber 5 as indicated by the arrow 13. Thereby, a high pressure ratio can be obtained, and supercharging can be efficiently performed in a large flow rate region.

  Next, a second embodiment of the present invention will be described. FIG. 3 is an explanatory view showing the periphery of the tongue 6 of the supercharged compressor 20 of this embodiment as a cross section. FIG. 4 is a block diagram showing the main components of an engine incorporating a turbocharger equipped with a supercharged compressor 20. An air flow meter 23 for measuring the amount of air flowing into the supercharged compressor 20 is provided upstream of the supercharged compressor 20, and an intercooler 24 is disposed downstream. The air supplied by the supercharged compressor 20 is supplied to the intercooler 24 and cooled, and then sent to the engine body 25. Exhaust gas discharged from the engine body 25 is supplied to a turbine (T in the figure) to further rotate the turbocharger.

  Such a supercharged compressor 20 is different from the supercharged compressor 1 of the first embodiment in that the movable wall 8 of the supercharged compressor 1 of the first embodiment is urged by a spring 9 so as to be projected and retracted toward the scroll chamber 5 side. On the other hand, in the supercharged compressor 20, the projecting and retracting is realized by the actuator driven by the motor 21. The drive of the motor 21 is controlled by an ECU (Electronic control unit) 22. The ECU 22 corresponds to a control unit in the present invention. Since other configurations are the same as those in the first embodiment, common components are denoted by the same reference numerals in the drawings, and detailed description thereof is omitted.

  The ECU 22 controls the drive of the motor 21 with reference to the information from the air flow meter 23, the rotation speed of the supercharged compressor 20, and the flow rate a obtained in advance from the flow rate-pressure ratio characteristic diagram shown in FIG. Do. Note that the flow rate-pressure ratio characteristic diagram shown in FIG. 5 is determined for each specification of the supercharged compressor 20, and a program assembled based on this flow rate-pressure ratio characteristic diagram is stored in the ECU 22. The ECU 22 controls the drive of the motor 21 in accordance with this program.

  When the flow rate of the supercharged compressor 20 is smaller than a, the winding start portion 10 and the winding end portion are moved as shown in FIG. Communication with 11 is cut off. For this reason, the air flowing through the scroll chamber 5 is discharged to the outside as indicated by the arrow 12 without recirculating through the scroll chamber 5. Thereby, the loss by recirculation can be avoided and supercharging can be performed efficiently in a small flow rate range.

  On the other hand, when the flow rate of the supercharged compressor 20 is less than a, the movable wall 8 is housed in the housing portion 7 by driving the motor 21, and the winding start portion 10 and the winding end portion as shown in FIG. 11 is communicated. For this reason, a part of the air flowing in the scroll chamber 5 is branched from the flow indicated by the arrow 12 and recirculated in the scroll chamber 5 as indicated by the arrow 13. Thereby, a high pressure ratio can be obtained, and supercharging can be efficiently performed in a large flow rate region.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope. For example, it can be set as the structure provided instead of the spring 9 in Example 1 with another elastic body. Moreover, although the actuator in Example 2 is driven by the motor 21, other motive power can also be used.

It is explanatory drawing which showed the tongue part periphery of the supercharged compressor of Example 1 as a cross section. It is the figure which looked at the supercharging compressor from the rotating shaft direction, and is explanatory drawing which shows arrangement | positioning and shape of the scroll chamber 5, Comprising: (a) is the state which the movable wall protruded, (b) is the movable wall It shows the stored state. It is explanatory drawing which showed the tongue part periphery of the supercharged compressor of Example 2 as a cross section. It is the block diagram which showed the main components of the engine in which the turbocharger provided with the supercharged compressor of Example 2 was incorporated. It is a flow-pressure ratio characteristic figure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 20 Supercharged compressor 2 Housing 3 Impeller 4 Diffuser 5 Scroll chamber 6 Tongue part 7 Storage part 8 Movable wall 9 Spring 10 Winding start part 11 Winding end part 21 Motor 22 ECU
23 Air flow meter 24 Intercooler 25 Engine body

Claims (5)

A centrifugal compressor comprising a movable wall that changes a communication state between a winding start portion and a winding end portion of a scroll chamber. A centrifugal compressor characterized in that a movable wall for changing a communication state between the winding start portion and the winding end portion is provided at a tongue portion where the winding start portion and the winding end portion of the scroll chamber merge. The centrifugal compressor according to claim 1 or 2,
The centrifugal compressor is characterized in that the movable wall protrudes toward the scroll chamber side in a small flow rate region and blocks communication between the winding start portion and the winding end portion. The centrifugal compressor according to claim 1 or 2,
The centrifugal compressor according to claim 1, wherein the movable wall includes an elastic body biasing toward the scroll chamber. The centrifugal compressor according to claim 1 or 2,
An actuator that moves into and out of the scroll chamber of the movable wall;
A control unit of the actuator;
A centrifugal compressor characterized by comprising:

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